Reinforced concrete is a structural member which maintains strength and durability for a long period of time by the mechanism that strong alkali in the concrete forms a passive film on the surface of steel reinforcement for preventing corrosion of the reinforcement.
However, as the concrete is decreased in alkalinity due to neutralization or chloride ions penetrate in the concrete, the passive film on the reinforcement surface is destroyed, allowing the reinforcement to be corroded. Therefore, there is an increasing demand for agents for preventing steel reinforcement in reinforced concrete from corrosion due to such deterioration.
Patent Documents 1 and 2: JP 4778189 and JP 5422791 disclose mixtures of an organosilicon compound and dimethylethanolamine or diethylethanolamine. However, these agents are still insufficient to prevent corrosion of reinforcement. Moreover, diethylethanolamine used as the amine compound is designated to a deleterious substance in the Japanese Cabinet Order for the Designation of the Poisonous and Deleterious Substances.
There is a desire to achieve more effective and safe corrosion prevention of steel reinforcement in reinforced concrete.